PRETORIA, South Africa (CNN) --Convicted former South African first lady Winnie Madikizela-Mandela says she has resigned from her positions in the African National Congress, but will remain a member of the party.

She released a statement shortly after a South African magistrate Friday sentenced Madikizela-Mandela, the ex-wife of South African President Nelson Mandela, to five years in prison -- one year to be suspended with good behavior -- on fraud and theft charges.

"This kind of crime is unacceptable and will not be tolerated," Magistrate Peet Johnson said, after the sentencing.

Madikizela-Mandela and co-conspirator Addy Moolman were convicted of multiple counts of fraud and theft for their involvement in a bank loan scandal. Moolman received a seven year sentence, with the possibility of two years suspended.

According to different interpretations of South Africa's criminal code, Madikizela-Mandela could serve as little as eight months or even none of her jail sentence.

Both of the accused were released on 10,000 Rand ($1,300) bail, pending their imminent appeals.

Amid heavy security inside and outside the courtroom, the magistrate Friday handed down the sentence, after requests from both the prosecutor and defense attorney not to give Madikizela-Mandela any jail time.

During opening statements, Prosecutor Jan Ferreira told a packed courtroom that a sentence of suspension with court supervision would be enough for the 66-year-old former first lady, citing her age and community involvement as overriding factors.

'Herself to blame'

However, Ferreira noted Madikizela-Mandela's lack of remorse in the 90 minutes of arguments.

"Should this end her political career, she has but only herself to blame," Ferreira said.

Defense Attorney Ismael Semenya suggested Madikizela-Mandela was only trying to help her personal secretary, who owed money to loan sharks.

Members of the general public were not allowed into the courtroom because of security concerns. People entering the courthouse were screened by metal detectors, and members of the media and family received additional hand searches.

Outside the Pretoria courthouse, a crowd of supporters and detractors of the former first lady gathered, monitored by police officers on horseback and bomb-sniffing dogs.

Friday morning's proceedings were briefly interrupted by two young men, one who stated to the courtroom: "I am willing to die by your side Mama."

The Congress of South African Students (COSAS) had threatened to close down government operations in Pretoria should Madikizela-Mandela be sentenced to jail, but Hunter-Gault said this no longer "appeared to be on the cards."

Madikizela-Mandela and Moolman were convicted of attempting to obtain financial loans for members of the African National Congress Women's League, which she chaired. She signed up to 50 letters for loans, but the ANC Women's League has only eight employees.

The convictions on theft included a phony funeral insurance scam in which money was pilfered from participants' accounts.

The convictions were the latest in a string of legal problems for Madikizela-Mandela, dating back to her 1991 conviction for kidnapping and accessory in the assault of a 14-year-old township boy, murdered by one of her associates. Her six-year sentence was suspended after an appeal.

Most recently, she has been fighting moves by parliament's public ethics committee to reprimand her for failing to declare donations and business interests believed to exceed her parliamentary salary. Associates say she is nearly destitute.

Solitary confinement

As Winnie Mandela, she became a worldwide anti-apartheid heroine when she stood in for her jailed husband, ANC leader, Nelson Mandela during his 27 years in prison.

She was also persecuted by the apartheid regime, twice jailed, put in solitary confinement, and later banished to a remote outpost.

She was by her husband's side when he was released but the couple were divorced in 1996.

Throughout her many trials and tribulations, Madikizela-Mandela has maintained strong support among many black South Africans.

Opposition leaders immediately called for her resignation from parliament. The ANC said it "respected and accepted" the verdict.